Temporal variability in emission category influence on organic matter aerosols in the Indian region

The dependence of carbonaceous aerosol properties, like radiation absorption and hygroscopicity, on the emission source of origin motivate this work. The influence of emission categories, including crop residue and forest burning, biofuel combustion, brick kilns, thermal power plants, diesel transport and "other industry'', is estimated on organic matter (OM) surface concentrations in the Indian ocean region. The approach uses general circulation model predicted OM surface concentrations during a ship cruise, identifies probable source regions for high concentration episodes using the potential source contribution function, and estimates collocated OM emissions resolved by category. Distinct source regions identified, are the Indo-Gangetic Plain during 20-30th January, 1999, and central/south India during 1-11th March, 1999. Contributing emission categories are primarily biofuel combustion (18 Gg) during 20-30th January, but a combination of forest burning (8 Gg), biofuel combustion (7 Gg) and crop residue (5 Gg) during 1-11th March. The magnitude of emission flux rather than spatial extent of an emission category, was seen to increase its influence on the receptor. This approach can be used to investigate seasonal and inter-annual variability in emission category influence on atmospheric pollutants. Citation: Cherian, R., C. Venkataraman, and S. Ramachandran (2009), Temporal variability in emission category influence on organic matter aerosols in the Indian region, Geophys. Res. Lett., 36, L06809, doi:10.1029/2008GL036311.